1. Field of the Invention
This invention relates to an optical disk recording/reproducing method and recording/reproducing apparatus and an optical disk and more particularly to a management method for managing a learning region of an optical disk.
2. Description of the Related Art
As is well known in the art, recently, an optical disk having a recoding capacity of 4.7 GB on one surface is put to practical use as an optical disk capable of recording information with high density. For example, a rewritable DVD-RAM (ECMA-330) and additionally writable +R (ECMA-349) and DVD-R (ECMA-338) and the like are provided.
Information is recorded/reproduced with respect to the above optical disk by forming an information recording layer on a transparent substrate and condensing laser light thereon. The strength of laser light is adequately changed according to the reproduction, recording and erase operations. Further, the optimum strengths of laser light at the recording time and erase time are inherently set for the respective optical disks. Therefore, in the optical disk apparatus, the strength of recording laser light is controlled to an optimum value (OPC: Optimum Power Control) when information is recorded on the optical disk. For example, in DVD-R, the strength of recording laser light is controlled to an optimum value (OPC) by recording and reproducing preset test information in a power calibration area which is an area set on the optical disk to learn the laser light strength before user information or the like is recorded.
As shown in an example disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2003-168216, the information area used for learning the laser light strength is previously provided with a certain amount of recording capacity in a specified position on the internal circumference side or outer circumference side with respect to the user information recording area of the disk. As a result, user information and the user information recording area are prevented from being destroyed by learning the laser light strength in the user information recording area.
Generally, the operation of learning the laser light strength is performed before information is first recorded after the disk is inserted or before information is recorded after a long period of time has elapsed from the preceding learning operation or after the environment condition of temperature or the like is changed. In this case, the learning area may be used up earlier than the user recording area is used up in some cases. For example, this happens in a case where the learning operation is not satisfactorily performed and a large part of the learning area is consumed, where a small amount of data is intermittently recorded with certain time intervals or where defects are present in the learning area. In such a case, if the learning area is previously provided with preset recording capacity in a specified portion on the internal circumference side or outer circumference side of the disk, there occurs a possibility that the entire portion of the learning area is used up although the user information recording area still has available remaining capacity.
The above problem tends to occur in the additionally writable disk. Since the strength of laser light for writing cannot be controlled to an optimum value if the learning area is used up, there are problems that the recording operation cannot be performed and the recording capacity substantially decreases even if an attempt is made to newly record user information in the user information recording area.